The present invention relates to an unmanned aircraft to be launched from a silo, or the like, by means of a rocket engine.
Aircraft of the type to which the invention pertains are launced on rails from a silo, i.e., a suitable container under utilization of a rocket engine. Subsequently, a propeller engine takes over for cruising the vehicle towards a target area. Wings are deployed subsequently to the launch so that the rocket-engine-launched vehicle proceeds by aerodynamic flight.
Aircraft of the type referred to above are sometimes called minidrones, or the like, and are, for example, used as attack vehicles against enemy radar equipment, particularly in air defense installations. These minidrones fly towards enemy territory, search for the installation of interest and attack it, possibly after flying temporarily in a holding mode. These minidrones require comparatively little expenditures, and but a few people are involved in their tactical use. Storage and transport must be simple; because many of them may be needed and are to be held in readiness for strategical reasons. The same is true in regard to maintenance and the launching procedure. Also, these crafts should occupy little space, as they should be kept in an unobtrusive manner.
An aircraft of the type outlined above is described, for example, in Aviation Week And Space Technology, Volume 109, Nov. 23, 1978, particularly pages 42 and 43. Propulsion of that craft is the result of rocket launching and subsequent aerodynamic flight. Wings, control foils, and propellers are all retracted during launching to be deployed only after departure from the launching silo. The wings, in particular, are normally folded back and are folded forward for deployment. Alternatively, the wings are rigid but pivotal about a center axis. Normally, they are folded in a position on the fuselage. After take-off, they are deployed by pivoting by 90 degrees.
Following launching of such a vehicle from a silo, a critical phase occurs during the transition from rocket propulsion to propeller-driven cruising. Since this phase occurs rather early, it may endanger personnel at the launch site if launching was not successful. Also, the craft may be lost. This transition phase may, for example, be unsuccessful when any of the retracted parts, which are needed for aerodynamic flight, are not or only insufficiently deployed. Also, the propeller and its drive may not start properly.